The concepts of minimally invasive dentistry and its impact on clinical practice: a survey with a group of Brazilian professionals

Abstract

This cross-sectional study aimed to assess the knowledge and attitudes of 123 Brazilian dentists in relation to the concepts and practice of minimally invasive dentistry (MID). Data were collected through a questionnaire developed and validated by experts. Statistical analysis was performed using an spss program and Pearson’s chi-square test. Most participants had up to 10 years experience after graduation (69.9%), were specialised (60.2%) and worked in public and private service (43.1%). Regarding current concepts of dental caries, 87.0% were unaware and 65.9% answered that the treatment involves only the restorative phase. In relation to caries lesion arrest, 39.8% replied that it depended on the total removal of carious tissue. Most of them were aware of MID procedures (82.1%) but 49.6% did not follow them in daily practice. From these participants, 48.4% did not believe in the technique or did not know how to perform it. Decisions on partial or total removal of carious dentine, behaviour in relation to the procedures (permanent or temporary) and the practice of MID were not influenced by how long since the professionals had graduated or become specialised. It can be concluded that scientific evidence reaches most of the professionals, but does not benefit all patients, as many practitioners still follow the principles of total removal of carious tissue. Teaching should include making professionals fully aware of the carious process and encourage them to fully adopt the techniques and attitudes of MID.

INTRODUCTION

In recent decades, research on the mechanisms of dental caries has sought a better understanding of its beginning and progression¹. It is not possible to explain its aetiology exclusively in terms of its primary factors as aspects such as access to health services and socioeconomic conditions of the population should be considered for the analysis of caries and its development².

Minimally invasive dentistry (MID) comprises the correct diagnosis of the patient’s disease activity, its treatment (not necessarily invasive) and the strategies of prevention and maintenance of dental and periodontal health. Thus, the treatment is directed at controlling the disease, and not just the lesions, through educating the patient regarding plaque control, obtaining positive habits as to diet and rational use of fluoride³.

Scientific progress and understanding of the pathogenesis of dental caries led to modifications of older concepts. The philosophy of MID is based on a series of innovations, technologies and methods of treatment and considers as its principle the systematic compliance to dental tissue-64., 5..

Several investigations have been developed in order to demonstrate the possibility of leaving carious tissue in the cavity intentionally. Partial removal of carious tissue is indicated for the treatment of deep carious lesions, without painful symptoms, in primary or permanent teeth. This is a conservative technique that reduces the risk of pulp exposure and does not cause adverse reactions to the patient⁶. Thus, this technique is preferred to total removal of carious tissue⁶.

In recent decades, a number of studies have shown satisfactory results when assessing carious lesions treated by considering its clinical, ultrastructural, microbiological and chemical aspects7., 8., 9., 10., 11., 12.. After partial removal of carious dentine and the hermetic sealing of cavities, the viability of bacteria beneath restorations was evaluated by many authors and they concluded that there is a decrease in bacterial growth, absence of microorganisms or inactivation. Thus, there would be no progression of carious lesions1., 9., 10., 11., 12..

Therefore, partial removal of carious dentine, followed by hermetic sealing of the cavity, is currently considered a good option in the treatment of primary teeth with deep cavities13., 14., 15.. Through these procedures, and associated with patient motivation, there is discontinuance of disease progression with maximum preservation of tooth structure and restoration of shape and lost functions. This avoids pulp exposure, simplifies the treatment and appropriately preserves the elements in the dental arch until exfoliation4., 16..

According to several authors8., 10., 17., 18., despite the advantages of minimally invasive procedures in the preservation of dental elements, recognition in the scientific community and its strong link with the proposed guidelines by public health policies, the practical application of these procedures is not yet widespread in public health programmes.

The available scientific knowledge allows major changes to be introduced in the management of dental caries. Thus, this study aimed to evaluate knowledge and the attitudes of a group of Brazilian dentists in relation to the concepts of MID.

METHODS

This cross-sectional study was developed in the city of Recife, capital of Pernambuco, one of nine federal units that comprise the northeast region of Brazil. The sample comprised 123 dentists who participated in a survey during a regional dentistry congress and formed part of a preliminary study considered as a basis for conducting a population-based study.

The instrument used for data collection was a questionnaire developed by a team of specialists in paediatric dentistry. In order to validate this instrument, a pilot study was conducted which aimed to verify the reliability of the instrument and confirm understanding of the questions by the survey participants. This survey was conducted with interviews carried out by three trained researchers. In the survey, sociodemographic data of dentists were recorded, such as gender, year of graduation, training institution, specialisation and the workplace. In addition, information was recorded about knowledge of the requirements for carious lesions arrestment (removal of carious tissue, choice of restorative material and quality of sealing) and concepts on the difference between caries lesion and dental caries disease and its treatment. The professional’s attitudes regarding the performance of minimally invasive procedures were also assessed in daily clinical practice.

This study was conducted in full accordance with the World Medical Association Declaration of Helsinki. The research project was approved by the Ethics Committee in Research of the Pernambuco State University (Protocol 02450112.1.0000.5207). All participants were informed about the research methodology and confirmed their participation by signing a free and clarified consent term that ensured confidentiality of data and personal information collected.

The data were computed on a database in spss (Social Package for Social Science, Chicago, IL, USA) version 13.0. A descriptive and inferential statistics was performed, using Pearson’s chi-square test at the 5% level of significance.

RESULTS

Of the participants, 61.8% were female and 38.2% were male. Most participants had up to 10 years experience after graduation (69.9%) in public institutions (86.2%) and 60.2% had some degree of specialisation; 27.7% of participants were specialists in paediatric dentistry, special care dentistry, public health and restorative dentistry and 32.5% were in the areas of surgery, endodontics, implants, prosthodontics and legal dentistry.

When asked about post-graduation studies (Master and Doctorate), only 17.1% had achieved these. It was observed that 88.6% had not participated in updating courses on diagnosis and treatment of caries in the previous 6 months.

It was found that a large number of participants (72.4%) attended children. Regarding workplace, most participants worked in public and private services (43.1%), 38.2% worked only in public service and only 18.7% worked in a private dental office.

In relation to knowledge about the concepts of caries lesions and dental caries disease (Table 1), most said there was no difference between them and showed no knowledge on the subject (87.0%). For treatment of caries, 65.9% showed no knowledge on the subject, answering that the treatment involved only the restoring stage; they did not mention aspects such as guidance, motivation or patient education (Table 1).

Table 1.

Distribution of participants in relation to knowledge demonstrated on the concepts of dental caries, its treatment and the requirements for caries lesion arrest

Variable	n	%
Concepts on dental caries
Showed knowledge	16	13.0
Showed no knowledge	107	87.0
Concepts of the treatment of dental caries
Showed knowledge	42	34.1
Showed no knowledge	81	65.9
Removal of carious dentine
It depends of total removal of carious dentine	49	39.8
Regardless of total removal	59	48.8
No answer	15	12.2
Material
It depends of the material	75	61.0
Regardless of the material	26	21.1
No answer	15	12.2
Efficient restoration (hermetic)
It depends of the restoration	104	84.6
Regardless of the restoration	6	4.9
No answer	13	10.6
Total	123	100.0

When asked about the necessary requirements for arrest of carious lesions, 39.8% said it depended on the total removal of carious tissue and 48.8% answered that it was not dependent on total removal. For most participants, arrest of the caries lesion also depended on the choice of material (61.0%) and on efficient restoration (84.6%) (Table 1).

Table 2 shows the distribution of participants according to the clinical practice of MID procedures. It was found that 82.1% received information about the technique of partial removal of carious tissue and hermetic sealing of the cavity; however only 49.6% said they used these procedures. Most of the participants considered these procedures as temporary (48.8%). Among those who performed MID procedures, the majority (65.6%) stated that they performed MID in any patient and 42.6% stated that they performed it in primary and young permanent teeth.

Table 2.

Distribution of participants according to the practice of minimally invasive dentistry (MID)

Variable	n	%
Knowledge about MID techniques
Yes	101	82.1
No	22	17.9
Total	123	100.0
Practice of MID
Yes	61	49.6
No	62	50.4
Total	123	100.0
Conduct in relation to the practice of MID
Permanent	47	38.2
Temporary	60	48.8
No answer	16	13.0
Total	123	100.0
Patients who used MID procedures
Any patient	40	65.6
Non-contributor patients	8	13.1
Disabled patients	1	1.6
Non-contributor and disabled patients	12	19.7
Total*	61	100.0
Dental elements used MID in procedures
Only primary teeth	16	26.2
Primary and permanent teeth	19	31.1
Primary and young permanent teeth	26	42.6
Total*	61	100.0
Reasons for not performing MID procedures
Did not believe in the technique	14	22.5
Did not know how to perform them	16	25.9
Did not have patient supervision	4	6.4
Did not perform restorative procedures	10	16.2
No answer	18	29.0
Total†	62	100.0

^*Refers to the group not performing MID procedures.

^†Refers to the group that not performing MID procedures.

In the group of professionals who stated that they did not perform MID procedures, it was found that the highest percentages were professionals who did not believe in the technique (22.5%) or were not aware of the procedures (25.9%) (Table 2).

Tables 3, 4 and 5 show that the decision for partial or total removal, and conduct in relation to MID procedures (permanent or temporary) and their practice, were not influenced by how long since professionals had graduated or how long they had studied (specialisation or postgraduation).

Table 3.

Assessment of removal of carious tissue according to how long since participants had graduated, become specialised or achieved a postgraduate degree (stricto sensu) and their attitude towards minimally invasive dentistry (MID) procedures

Variable	Removal of carious tissue						P
	Total		Partial		Total
	n	%	n	%	n	%
Graduated for
Up to 10 years	33	44.6	41	55.4	74	100.0	0.811
Over 10 years	16	47.1	18	52.9	34	100.0
Total	49	45.4	59	54.6	108	100.0
Specialisation
Yes	26	41.9	36	58.1	62	100.0	0.405
No	23	50.0	23	50.0	46	100.0
Total	49	45.4	59	54.6	108	100.0
Postgraduation stricto sensu
Yes	4	26.7	11	73.3	15	100.0	0.117
No	45	48.4	48	51.6	93	100.0
Total	49	45.4	59	54.6	108	100.0
Attitude toward MID procedures
Permanent	7	16.7	35	83.3	42	100.0	< 0.001
Temporary	33	62.3	20	37.7	53	100.0
No answer	9	69.2	4	30.8	13	100.0
Total	49	45.4	59	54.6	108	100.0

Table 4.

Assessment of the performance of minimally invasive dentistry (MID) procedures according to how since participants had graduated, become specialised or achieved a postgraduate degree

Variable	Attitude toward MID procedures						P
	Permanent		Temporary		Total
	n	%	n	%	n	%
Graduated for
Up to 10 years	33	42.9	44	57.1	77	100.0	0.721
Over 10 years	14	46.7	16	53.3	30	100.0
Total	47	43.9	60	56.1	107	100.0
Specialisation
Yes	30	49.2	31	50.8	61	100.0	0.207
No	17	37.0	29	63.0	46	100.0
Total	47	43.9	60	56.1	107	100.0
Postgraduation stricto sensu
Yes	11	64.7	6	35.3	17	100.0	0.060
No	36	40.0	54	60.0	90	100.0
Total	47	43.9	60	56.1	107	100.0

Table 5.

Assessment of the practice of minimally invasive dentistry (MID) according to how long since participants graduated, become specialised or achieved a postgraduate degree (stricto sensu), and the knowledge of the technique and procedure

Variable	Practice of MID						P
	Yes		No		Total
	n	%	n	%	n	%
Graduated for
Up to 10 years	42	48.8	44	51.2	86	100.0	0.798
Over 10 years	19	51.4	18	48.6	37	100.0
Total	61	49.6	62	50.4	123	100.0
Specialisation
Yes	40	54.1	34	45.9	74	100.0	0.224
No	21	42.9	28	57.1	49	100.0
Total	61	49.6	62	50.4	123	100.0
Postgraduation stricto sensu
Yes	12	57.1	9	42.1	21	100.0	0.447
No	49	48.0	53	52.0	102	100.0
Total	61	49.6	62	50.4	123	100.0
Knowledge of MID techniques
Yes	60	59.4	41	40.6	101	100.0	< 0.001
No	1	4.5	21	95.5	22	100.0
Total	61	49.6	62	50.4	123	100.0
Procedure
Permanent	36	76.6	11	23.4	47	100.0	< 0.001
Temporary	24	40.0	36	60.0	60	100.0
No answer	1	6.3	15	93.8	16	100.0
Total	61	49.6	62	50.4	123	100.0

In Table 3, there was a statistically significant association between carious tissue removal and attitude of the professional toward MID procedures (P < 0.001). It was observed that 83.3% of professionals considered MIP as a permanent technique, and they were in the group that recommended the partial removal of carious tissue, whereas 62.3% of those who regarded the technique as temporary recommended total removal of carious tissue.

A statistically significant association was observed between the practice of MIP, the professionals’ knowledge of the technique (P < 0.001) and conducting the technique (P < 0.001) (Table 5). Most professionals who knew the technique, performed it (59.4%), while the vast majority were unaware of MID procedures (95.5%) and did not perform them. Furthermore, 76.6% of those who regarded it as definitive, performed MID, whereas most of those who regarded it as temporary, did not perform it (60.0%).

Table 6 shows an assessment of knowledge of MID procedures, according to how long since participants had graduated and the reasons why they did not practice the technique. It was found that there was no statistically significant association between how long since they had graduated and their knowledge of the technique. From recent college graduates to those who had graduated for more than 10 years, most of already knew about MIP.

Table 6.

Assessment of the knowledge of minimally invasive dentistry (MID) procedures according to how long since participants had graduated and the reasons for not performing the technique

Variable	Knowledge of MID techniques						P
	Yes		No		Total
	n	%	n	%	n	%
Graduated for
Up to 5 years	50	82.0	11	18.0	61	100.0	0.957
From 5 to 10 years	21	84.0	4	16.0	25	100.0
Over 10 years	30	81.1	7	18.9	37	100.0
Total	22	17.0	101	82.1	123	100.0
Reasons for not performing MID procedures
Did not believe in the technique	12	85.7	2	14.3	14	100.0	< 0.001
Did not know how to perform	5	31.3	11	68.8	16	100.0
Others	14	100.0	0	0.0	14	100.0
No answer	10	55.6	8	44.4	18	100.0
Total*	41	66.1	21	33.9	62	100.0

^*Refers to the group of professionals who did not perform MID.

It was found that 85.7% of participants, despite having knowledge of MID did not believe in the technique and this result was statistically significant (P < 0.001) (Table 6).

DISCUSSION

This research was carried out on a sample that has great responsibility for the diagnosis and treatment of dental caries in the population, as most professionals work in public and private service. It is known that the Brazilian public service provides care for a less-favoured population that needs a comprehensive approach regarding dental caries, which is considered a more concentrated disease. However, the results showed that most professionals surveyed showed no knowledge of current aspects of the diagnosis and treatment of caries, leading to treatment only of sequelae of the disease. Although a large percentage of professionals are experts, most of had been not updated in the subject for the last 6 months.

In Brazil, dental caries is still a public health issue that mobilises most of the efforts and resources in this field. Dental caries in school children has decreased, but this reduction has been smaller in the group of preschoolers. These results suggest that the conduct of professionals in the public service makes it difficult to control dental caries in this population. It is important to have a complete knowledge of dental caries in order to inform any decision about its treatment and control; it is not worthwhile simply treating the sequelae if the cause of the problem is not resolved, thus perpetuating a repetitious restorative cycle.

No statistically significant difference was observed between how long since participants had graduated, and how many years of study (through specialisation courses, master and doctorate), and the knowledge and attitudes of professionals in relation to MID. During the interviews it was possible to observe highly specialised professionals, unfamiliar with current aspects of dental caries, treating it only from the restoration point of view. In contrast, the great majority of professionals showed knowledge of the technique of partial removal of carious tissue and hermetic sealing of the cavity, although a significant number of professionals did not perform these procedures, disregarding the effectiveness of the technique. It is apparent, therefore, that scientific knowledge reaches most professionals but the technique does not reach all their patients, as many professionals still follow the basic principle that has ruled the surgery of dentistry for centuries, namely, the elimination of any infected tissue of the lesion¹⁸, even though the scientific evidence shows that such a procedure is no longer necessary.

These results agree with two other studies with similar methodologies19., 20.. Oen et al.¹⁹ found that most professionals interviewed indicated that they would remove all carious tissue even if the procedure involved the pulp exposure. Only one in five participants would choose to continue with partial removal of caries and a slightly higher fraction would initiate endodontic treatment of the patient. In the study of Qudeimat et al.²⁰, most participants would choose pulpotomy for treatment in cases of deep carious lesions²¹.

In this study, we found that most participants stated that they performed MID procedures. However, it was found that the majority consider this procedure as temporary, probably following the principles of expectant treatment, where the tooth will afterwards receive a further procedure to conclude the removal of remaining dentine and then undergo permanent restoration. However, this type of treatment entails disadvantages: the mechanical procedures to reopen the cavity to remove the remainder of carious dentine may increase the risk of pulp exposure, in addition to making the patient undergo an additional and unnecessary medical procedure²¹.

Studies have shown that treatment of deep carious lesions may be done in a single session, with the placement of the final restoration even without complete removal of carious dentine10., 21.. After the initial excavation and sealing of the cavity, the restoration process of tubular sclerosis and deposition of tertiary dentine is encouraged. The persistence of microorganisms is irrelevant. These will be buried by sealing the restoration and the reduction in permeability of the remaining dentine²². In view of this, the first stage of the expectant treatment (i.e. the removal of only a superficial, necrotic and fragmented layer of the bottom wall of the cavity and total removal of the surrounding walls) is enough to prevent the progression of caries and may be used as a permanent treatment²².

The fact that most professionals do not believe in the technique of partial removal of carious tissue and perform this only as a temporary procedure reveals that the use of this technique as an alternative to conventional curative treatment is still not well accepted and still considered an inferior procedure, as observed in other studies8., 10., 17., 18..

Despite the advances in research related to better understanding of the initiation and progression of caries, it was observed that the conventional treatment with invasive interventions is still the reality of dental treatment. Despite being an essential approach aimed at promoting health, it is still not a common practice among professionals¹. The results of this study show that the dentists surveyed apparently need more evidence to change their treatment in relation to total or partial removal of carious dentine. It is necessary to focus teaching in dentistry on the areas of cariology and restorative dentistry, with the aim of training professionals who know and understand the carious process as a whole and not just restorative techniques. This will encourage professionals to adopt entirely the techniques and procedures of this new way of practicing dentistry.

Acknowledgements

The authors acknowledge the Brazilian Federal Agency for the Support and Evaluation of Graduate Education (CAPES) for the financial support; and the Post-Graduation Program in Dentistry of School of Dentistry, Pernambuco State University (FOP/UPE).

Competing interests

None declared.